In the production of tubular knitted fabric, it is conventional for the fabric to be knitted in circular form, in semi-continuous lengths. The knitting operation proceeds in the manner of a continuous spiral, continuously adding to the trailing edge of the emerging tube of fabric. In a typical circular knitting machine, a number of knitting stages are provided around a circular platform such that, in each cycle of knitting, a plurality of courses are knitted into the continuously constructed fabric tube. The spiral structure of the fabric is thus readily evident in a typical production fabric, where a number of courses are knitted in each cycle.
In the manufacture of striped circular knitted fabrics, such as for use in the manufacture of polo shirts and the like, the spiral orientation of the stripes is very noticeable in the knitted tube. Typically, therefore, in the production of outer wear garments, particularly of striped fabric, it is conventional to process the knitted circular fabric by slitting it lengthwise along its full length, laterally displacing the cut edges a full stripe width, one with respect to the other, and sewing the seam closed with the stripes aligned in displaced positions. This results in stripes which run circularly around the fabric tube, at right angles to its axis, rather than the original spirally configured stripes. Typical equipment for performing this operation is shown in the Walter et al. U.S. Pat. No. 2,467,281. The operation performed is normally referred to as stripe matching.
In the typical finish processing of tubular knitted fabric, the tubular fabric material is flattened and spread laterally to a predetermined, uniform width. It is then geometrically stabilized by being steamed while on the spreader and then immediately passed through an opposed pair of calender rolls and thence to an appropriate gathering station, where the fabric is gathered in either roll or folded form. In the finishing operations, it is highly desirable to orient the fabric so that the sewn seam is located exactly at the edge extremity of the fabric, as the fabric passes over the spreader and through the steaming and calendering stations. Heretofore, this has been achieved only by the continuous attention of a vigilant machine operator, feeding the fabric onto the entry end of the fabric spreader and carefully aligning and twisting the continuously advancing fabric tube in order to position the seam at or near the edge extremity. Under the best of circumstances, however, it has been difficult to achieve effective results with this manual practice as previously employed in the industry.
In accordance with the present invention, a finishing apparatus is provided which incorporates a novel and advantageous mechanism for effecting precise rotational orientation of the fabric tube relative to the spreader frame, such that proper and uniform orientation of the sewn seam at or near the precise edge extremity of the fabric tube is readily achieved. More importantly, the apparatus of the invention accommodates the automatic sensing of the orientation of the fabric seam and manipulation of the fabric, as necessary, to maintain an accurate alignment of the seam in the desired position.
Pursuant to a specific aspect of the invention, the finishing equipment is provided with a modified form of spreader frame, including a section arranged for cooperation with upper and lower controllable orienting rollers. The orienting rollers desirably contact the fabric substantially across its width, and are normally disposed at right angles to the axis of movement of the fabric, so as to have a neutral effect on the orientation. When the fabric tube requires orientation in one direction or the other, the orienting rolls are shifted angularly, so that a rotational component is imparted to the advancing fabric tube, in a direction tending to return the misaligned seam to its desired position at the edge extremity.
In the simplest form of the invention, manipulation of the orienting rolls may be accomplished manually. While this requires the attention of an operator, the operator demands are much less severe than where it is required to continuously feed and orient the fabric entirely by hand.
More desirably, however, the apparatus of the invention is equipped to provide for automatic sensing of the seam location and automatic adjustment of the orienting rolls to compensate for any departure from the desired position. To this end, a stripe matching operation, which precedes the finishing, may be designed to include the step of laying in a fine metallic yarn along the seam. The seam could, in fact, be actually sewn with the metallic yarn. However, it is relatively more expensive than conventional yarns and serves its purpose just as well, and at less expense, as a laid-in component. The finishing frame of the new apparatus is designed to accommodate the presence of a sensing device, which is responsive to the position of the metallic yarn, which, of course, is the position of the seam itself. Upon sensing of a displacement of the seam from its normal, edge extremity position, a mechanism is activated to adjust the orienting rolls proportionately, to impart a correcting rotational component to the advancing fabric tube. The mechanism and process of the invention enable a sensitive, yet stable control to be exercised over the fabric, so that the edge seam is aligned with a great deal of precision and uniformity in the finished product, enabling a higher quality product to be achieved with a reduced labor expense.
For a more complete understanding of the above and other features and advantages of the invention, references should be made to the following detailed description of a preferred embodiment, and to the accompanying drawings.